Religious cleric Mohammad Mukhtar said: “It is the duty of Muslims to react. When their holy book, the Koran, gets burnt in public, then there is nothing left. If this happens, I think people’s first reaction will be to kill any Americans they come across.”

The Secretary General of the Arab League has denounced the plan as the work of a “fanatic”.

Meanwhile, Iran has warned if the protest goes ahead, the reaction will be “uncontrollable”.

Protesters also gathered in Indonesia, the world’s most populous Muslim nation.

This group in Jakarta urged the US government to step in to calm the brewing storm.